Biological Opinions - Bureau of Reclamation

turbine venting program, augment gravel and LWD downstream of IGD, target 28 cold water
refugia sites along the mainstem Klamath River for improvement and maintenance of habitat
complexity and cover, and fund actions that address limiting factors for coho salmon in the
Shasta and Scott rivers.
NMFS expects implementation of a turbine venting program to improve habitat function by
providing more suitable dissolved oxygen for juvenile summer rearing for approximately six
miles downstream of IGD. NMFS also expects mainstem habitat in this reach will be improved
in the next nine years, such that foraging opportunities are improved below IGD resulting in
improved summer rearing and foraging habitat. Overall, the PacifiCorp HCP should decrease
the extinction risk of the Upper Klamath population. Improving connectivity and increasing
access to thermal refugia and productive tributary rearing and spawning sites, increasing
dissolved oxygen levels below IGD, replenishing gravel and LWD at strategic locations, and
diminishing disease prevalence is expected to collectively improve the survival probability for
coho salmon in the Upper Klamath, Middle Klamath, Shasta, and Scott river populations.
NMFS expects many of activities discussed in the Environmental Baseline section will continue
(e.g., timber management, habitat restoration, agricultural activities, tribal harvest). In addition,
climate information indicates that the Klamath River basin is likely to experience a wide
variation in hydrologic conditions (Pagano and Garen 2005), with continued warm spring
periods as experienced in the last decade (Van Kirk and Naman 2008). While NMFS does not
have a model to predict water temperature increases in the next 10 years, NMFS expects that
recent trends of increasing water temperatures in the Klamath River basin during the summer are
likely to continue. Elevated water temperatures in the tributaries and mainstem Klamath River
will decrease the available thermal refugia downstream of IGD, and will increase stress,
morbidity, or mortality of coho salmon juveniles.
Average annual air temperature in the upper Klamath Basin has been increasing over several
decades, snow water equivalent has been declining, and both these trends are predicted to get
worse. Reclamation (2011a) projected that snow water equivalent during the 2020s will decrease
throughout most of the Klamath Basin, often dramatically, from values in the 1990s.
12.6.1 Effects of the proposed action to the Interior Klamath Stratum populations
As described in the Effects to Individuals section (i.e., section 12.4), the proposed action results
in adverse effects to the coho salmon. Some of these adverse effects are minimized by the flow
variability incorporated into the proposed action, the near real-time disease management, and the
$500,000 annual restoration funding. A summary of these adverse effects and minimization
measures is presented below. The coho salmon populations closest to IGD are expected to be
most adversely affected. The coho salmon populations adversely affected the most to the least
are the Upper Klamath, Shasta, Scott, and Middle Klamath Rivers populations. The Salmon
River population is expected to have minimal adverse effects resulting from the proposed action.
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